Buy or not?

Hi guys,

I was thinking about getting the Gazelle and wanted to ask the community if it is worth it.

For me worth it is based on whether it simulates accurately the systems, engine, transmission, and flight model.

For example, does it simulate?: EGT, freewheeling unit, VRS, torque limits, etc.

Thank you all.

Not sure about freewheeling, the rest are simulated. The systems are completely accurate, specially the Viviane.

If by "freewheeling", you mean "autorotation" (i.e. landing without engine power, using the auto-gyro effect of the rotor), then yes. I did it a few nights ago... rather harrowing, but I made it down in one piece!

If by "freewheeling", you mean "autorotation" (i.e. landing without engine power, using the auto-gyro effect of the rotor), then yes. I did it a few nights ago... rather harrowing, but I made it down in one piece!

No, I mean the freewheeling unit. It is a sprag clutch (or other solutions) that prevents the rotor to drive the engine or in the Gazelle case the power turbine.

Can you split the needles in the dual tachometer if you throttle down suddenly?

I do not know. But I know the gazelle flight model and behaviour is not as accurate as helicopter models by ED / ex belsimtek. Keep this in mind.

I do not know. But I know the gazelle flight model and behaviour is not as accurate as helicopter models by ED / ex belsimtek. Keep this in mind.

Interesting. You have any information as to why is that?

Ok, I just saw in this video that the engine is not correctly modeled so I'll hold off for a while until it gets more love.

Explanation: the long needle (N2) is ahead of the short needle (NR). That could never happen IRL due to the way a helicopter is built.

The only thing that I can think of is that Polyshop coded the long needle to show the N1 which not only isnt how it is IRL but it would not make any sense either.

the long needle shows turbine RPM and the short needle shows rotor RPM.

im amazed he managed to start it that way. because you should start the turbine get it to idle at 25000 rpm then increase throttle to 29000 when the centrifugal clutch engages. then wait until the short needle catches up (the rotor). then increase throttle to full keeping the needles together.

in that video he does not wait till idle and just rams the throttle full while its starting. the turbine goes to full and the rotor rpm catches up.. in RL the clutch would have burned out.

in my above example the turbine fails (or it did) if you increased throttle too quickly. and don't keep the needles together.

anyway he is not even close to doing the manual start procedure in that vid.

im going to have to see if that craziness works for myself.

the long needle shows turbine RPM and the short needle shows rotor RPM.

 

im amazed he managed to start it that way. because you should start the turbine get it to idle at 25000 rpm then increase throttle to 29000 when the centrifugal clutch engages. then wait until the short needle catches up (the rotor). then increase throttle to full keeping the needles together.

 

in that video he does not wait till idle and just rams the throttle full while its starting. the turbine goes to full and the rotor rpm catches up.. in RL the clutch would have burned out.

 

in my above example the turbine fails (or it did) if you increased throttle too quickly. and don't keep the needles together.

 

anyway he is not even close to doing the manual start procedure in that vid.

 

im going to have to see if that craziness works for myself.

I'm not sure you know what a turbine is or how many turbines the Gazelle has. What I described stands, it is not arguable as it depicts Helicopter engines IRL.

It doesn't matter the guy follows or not correct procedures. The behaviour isn't correct anyway.

When you say turbine RPM, do you know there are two of them? Which one do you refer to?

A turboprop engine like the Gazelle usually has a compressor, a compressor turbine and a power turbine. The tachometer MUST show power turbine rpm and rotor rpm. That's how it is.

If the DCS Gazelle shows turbine rpm then it isn't modeled correctly, if it shows compressor rpm then it is not showing what it shows IRL.

Either way it's done incorrectly.

im going to have to see if that craziness works for myself.

The video is from 2016, before clutch damage was modelled - if you were to do that in the current version -

the centrifugal friction clutch overheats and destroys it's self due to excessive torque / clutch slip in about 25 seconds.

In game the damage is modelled as a 'bang' destroyed/no functioning engine and shrapnel damage to the engine cowling.

I'm not sure you know what a turbine is or how many turbines the Gazelle has. What I described stands, it is not arguable as it depicts Helicopter engines IRL.

 

It doesn't matter the guy follows or not correct procedures. The behaviour isn't correct anyway.

 

When you say turbine RPM, do you know there are two of them? Which one do you refer to?

 

A turboprop engine like the Gazelle usually has a compressor, a compressor turbine and a power turbine. The tachometer MUST show power turbine rpm and rotor rpm. That's how it is.

 

If the DCS Gazelle shows turbine rpm then it isn't modeled correctly, if it shows compressor rpm then it is not showing what it shows IRL.

 

Either way it's done incorrectly.

I am sorry, but you can't come here and say it's wrong without giving a prove of your data. Just a 5 min search on internet will make you see, that you are wrong.

You can read perfectly RPM TURB

he has engine damage turned off in the special tab to start it like that.

just checked

I am sorry, but you can't come here and say it's wrong without giving a prove of your data. Just a 5 min search on internet will make you see, that you are wrong.

 

 

You can read perfectly RPM TURB

Are you serious? I don't want to be rude, but it looks like you're not reading any of my posts.

I know it writes TURB, and I explained that

If the DCS Gazelle shows turbine rpm then it isn't modeled correctly, if it shows compressor rpm then it is not showing what it shows IRL.

 

Either way it's done incorrectly.

When I say compressor RPM we are talking about the compressor TURBINE rpm, so TURB doesnt mean anything.

Either way it's modeled incorrectly

A turboprop engine like the Gazelle usually has a compressor, a compressor turbine and a power turbine. The tachometer MUST show power turbine rpm and rotor rpm. That's how it is.

The Gazelle doesn't have a power turbine, it has a mechanical centrifugal clutch, above 28,500 RPM with the engine and main rotor in sync i.e. no clutch slippage, it's effectively a solid drive shaft with a sprag clutch (freewheel device) for emergencies.

The compressor turbine idles at 25,500 RPM at which speed, the centrifugal clutch remains disengaged and the main rotor stationary/ undriven.

Increasing the fuel control lever (governor), the turbine increases in speed until about 28,500 RPM, at which point the centrifugal clutch starts to engage and drive the main rotor (with clutch slip), excessive power/clutch slip will destroy the transmission, so the main rotor RPM should be allowed to sync with the clutch/turbine RPM and power slowly increases afterwards.

The Gazelle doesn't have a power turbine, it has a mechanical centrifugal clutch, above 28,500 RPM with the engine and main rotor in sync i.e. no clutch slippage, it's effectively a solid drive shaft with a sprag clutch (freewheel device) for emergencies.

 

The compressor turbine idles at 25,500 RPM at which speed, the centrifugal clutch remains disengaged and the main rotor stationary/ undriven.

 

Increasing the fuel control level (governor), the turbine increases in speed until about 28,500 RPM, at which point the centrifugal clutch starts to engage and drive the main rotor (with clutch slip), excessive power/clutch slip will destroy the transmission, so the main rotor RPM should be allowed to sync with the clutch/turbine RPM and power slowly increases afterwards.

Ok, I didnt know about the centrigugal clutch. Thank you for bringing that to my attention.

I will investigate further.

Well, this was embarrassing.

thanks Ramsay, I didn't know that the gazelle did not have the clutch in 2016.

why I thought it was crazy :)

The Gazelle doesn't have a power turbine, it has a mechanical centrifugal clutch, above 28,500 RPM with the engine and main rotor in sync i.e. no clutch slippage, it's effectively a solid drive shaft with a sprag clutch (freewheel device) for emergencies.

 

The compressor turbine idles at 25,500 RPM at which speed, the centrifugal clutch remains disengaged and the main rotor stationary/ undriven.

 

Increasing the fuel control lever (governor), the turbine increases in speed until about 28,500 RPM, at which point the centrifugal clutch starts to engage and drive the main rotor (with clutch slip), excessive power/clutch slip will destroy the transmission, so the main rotor RPM should be allowed to sync with the clutch/turbine RPM and power slowly increases afterwards.

Ramsay, can you check for me if the DCS Gazelle simulates the freewheeling unit? For example try reducing the throttle suddenly and check if you see the needles splitting.

Ramsay, can you check for me if the DCS Gazelle simulates the freewheeling unit? For example try reducing the throttle suddenly and check if you see the needles splitting.

TL;DR:

It's pretty hard to be sure, as when the Turbine RPM drops below 27,000 RPM, the clutch disengages (the animation for 'PgDn' - 'Fuel Control Lever closed' is somewhat slow), either way the Turbine and rotor RPM needles do 'split'.

Expanded Detail:

Although the Gazelle FM has improved since release, it still feels 'off' compared to BST's Huey or Mi-8, the best way I could describe it to someone who hasn't flown it is that it's as if the FM was modelled with the SAS/auto-pilot always engaged.

• IGE is less than the Huey but it has a smaller rotor, rather than settle into IGE, it tends to 'bounce' either sinking below or rising above IGE equilibrium (unless damped by pilot input).

As IGE is less, auto-rotations are quite a bit harder than in the Huey.

• VRS is hard to enter and last time I checked, even in what looked like a well developed VRS - a fistfull of collective would arrest descent.

• With risk of 1.15, I'd say the FM falls somewhere between BST's and ARMA 3.

Note: Although the Gazelle FM feels very RC like, I still haven't been able to replicate all the RL tricks demo'ed at airshows.

• IMHO the Gazelle's main strengths are it's instrumentation/3D modelling, SP Campaign and multi-crew.

Comment

It's not a bad module if you're looking for something different to the UH-1H, Mi-8 or Ka-50 (there's supposed to be ongoing development and 'good 'things' coming).

However, if you are looking at the Gazelle for a better FM than the Huey/Mi-8, I'd suggest it's probably not for you.

TL;DR:

 

It's pretty hard to be sure, as when the Turbine RPM drops below 27,000 RPM, the clutch disengages (the animation for 'PgDn' - 'Fuel Control Lever closed' is somewhat slow), either way the Turbine and rotor RPM needles do 'split'.

 

Expanded Detail:

 

Although the Gazelle FM has improved since release, it still feels 'off' compared to BST's Huey or Mi-8, the best way I could describe it to someone who hasn't flown it is that it's as if the FM was modelled with the SAS/auto-pilot always engaged.

 

• IGE is less than the Huey but it has a smaller rotor, rather than settle into IGE, it tends to 'bounce' either sinking below or rising above IGE equilibrium (unless damped by pilot input).

 

As IGE is less, auto-rotations are quite a bit harder than in the Huey.

 

• VRS is hard to enter and last time I checked, even in what looked like a well developed VRS - a fistfull of collective would arrest descent.

 

• With risk of 1.15, I'd say the FM falls somewhere between BST's and ARMA 3.

 

Note: Although the Gazelle FM feels very RC like, I still haven't been able to replicate all the RL tricks demo'ed at airshows.

 

• IMHO the Gazelle's main strengths are it's instrumentation/3D modelling, SP Campaign and multi-crew.

 

Comment

 

It's not a bad module if you're looking for something different to the UH-1H, Mi-8 or Ka-50 (there's supposed to be ongoing development and 'good 'things' coming).

 

However, if you are looking at the Gazelle for a better FM than the Huey/Mi-8, I'd suggest it's probably not for you.

So how do pilots do IRL to make a freewheeling unit check? All helos I've flown had that procedure in checklist. But I've never flown a fixed shaft engine like the Gazelle, only free turbine ones (that's why I assumed before this was one as well).

I guess you could throttle down without letting RPM to drop below clutch disengage threshold and that way we should definetly see a needle split with the short arrow always ahead of the long one. If they dont split or if they split with the long one higher than the short one, then the freewheeling unit is broken and the helo must never leave the ground or the simulation is incorrectly coded.

@theinmigrant

can't recommend the module. I'm waiting since release that it get's fixed (2016). FM is extremely off, something like a dirty hack of a plane FM with VTOL capability. You can even hear the pilot's heavy breathing when you "pull some G's". It's not on par with the other DCS modules.

+1

Sorry for giving this statement for the only german 3rd party developer.

Not sure about freewheeling, the rest are simulated. The systems are completely accurate, specially the Viviane.

Isnt the Viviane almost the only thing that actually is inaccurate because of being classified? For example they said that the symbology is completely different from the real thing

And thats not even going into its "locking" mechanism, how that causes lots of stuttering while moving, and the ranging laser being unreliable.

if you ignore whats wrong and focus on whats right you can have fun in the gazelle.

as ramsay said the smaller rotor effects IGE but it will also provide less gyroscopic stability. why she is more unstable in pitch and roll. than all the other helicopters.

my problem is she feels too floaty for a helicopter that is at its airframes maximum weight. with no weapons and a full tank of gas.

the other choppers do a better job of conveying a sense of mass.

and the SAS feeling like it is always on.

and some odd pedal behaviour but I assume that's the fenestron tail.

no VRS. so you can stop on a dime.

I don't regret buying it.

all the helicopters flight models could be improved with the addition of loss of tail rotor effectiveness, for instance. (not the ka-50 for obvious reasons)

so nothing is perfect.

So how do pilots do IRL to make a freewheeling unit check?

On the ground, it's easy to see the needle split, it occurs as soon as the fuel control is closed i.e. well above the max clutch engagement speed of 34,000 RPM

I guess you could throttle down without letting RPM to drop below clutch disengage threshold and that way we should definetly see a needle split with the short arrow always ahead of the long one. If they dont split or if they split with the long one higher than the short one, then the freewheeling unit is broken and the helo must never leave the ground or the simulation is incorrectly coded.

With the Gazelle, it's important you reference which needles you mean as the long/short needles are different to the Huey's duel tacho.

In the Gazelle the long needle is engine RPM @ 25,500 - 43,500 and the short needle the rotor RPM @ 0 - 378

During DCS auto-rotations, my attention is on the airspeed and the short rotor RPM needle, I'm aware of the needle split but it's not my main focus.